JP2007090656A - Translucent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a translucent article comprising a laminated body including one or more sets of adjacent two layers each having a different refractive index from the other in which a reflection loss of a transmitted light on the boundary face between the two layers caused by the refractive index difference of the two layers and/or an interference fringe generated by the boundary face are eliminated or decreased, while a haze does not increase. <P>SOLUTION: The translucent article comprising a laminated body including one or more sets of adjacent two layers each having a different refractive index from the other wherein at least one set of the boundary face out of the adjacent two layers has fine convexoconcaves is characterized in that the convexoconcave shape has a relation PMAX≤λMIN where λMIN is a minimum wave length in vacuum of the visible light wave spectrum and PMAX is a period at a most convex part of the fine convexoconcaves, and that an occupying rate of a sectional area of a translucent layer at the side on which the most convex part is formed in an imaginary sectional plane obtained by cutting the fine convexoconcaves with a plane orthogonal to the convexoconcave direction thereof is continuously gradually increased as it goes from the most convex part of the fine convexoconcaves to a most concave part and comes to 100% at the most concave part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used for window materials for display parts in various devices, surface plates for transparent touch panels, various optical elements such as lenses, constituent members for various surface plates for image display devices and image pickup devices, window materials for buildings, etc. It relates to a translucent article that can be made.

Conventionally, as window materials for display parts in various devices, surface plates such as transparent touch panels, various optical elements such as lenses, constituent members of various surface plates for image display devices and image pickup devices, window materials for buildings, etc. 2 Various translucent articles formed by laminating transparent layers are used. For example, Patent Document 1 discloses a scratch-resistant article in which a surface protective layer obtained by curing an ionizing radiation curable resin is formed on one surface of a resin film base material as a translucent article including a laminate of two transparent layers. A functional composite film is disclosed. As described above, when the first transparent layer (resin film substrate) T1 is provided with insufficient stain resistance, scratch resistance, etc., the second transparent layer (surface protection) is necessarily formed. For the layer T2, it is necessary to select a material different from that of the first transparent layer T1. As a result, the refractive index N1 of the first transparent layer T1 and the refractive index N2 of the second transparent layer T2 are usually different.
As described above, in the translucent article, the two transparent layers are usually laminated because there is a limit to the performance that can be obtained with only one layer made of the same material. This is because the second transparent layer is laminated to supplement the insufficient performance. Accordingly, since the two layers to be laminated are made of different materials, the refractive indexes are often different.

As shown in FIG. 13, when the refractive indexes of the adjacent layers T1 and T2 change discontinuously with the interface I as a boundary, light reflection occurs at the interface I. As a result, first of all, with respect to the incident light L _IN, the problem that the transmitted light loss due to the interface reflection light L _R is generated. More specifically, the incident light L _IN are other reflected light L _r ¹ reflected directly at the interface I, the transmitted light of the results of multiple reflections within the layer ^{_{T2 L t 3, L t 5}} , ··, L t n In addition, the transmitted light is lost due to the interface reflected light L _R that is also integrated. Secondly, as a result of multiple reflections between the front surface and the back surface (interface I with the layer T1) of the layer T2, transmitted light L _t ² , L _t ⁴ , L _t having a phase difference transmitted from the front surface is obtained. ⁶ ,. . The interference of L _t ^{n + 1} causes the problem that the transmitted light L _OUT is modulated and interference fringes are generated.

In order to eliminate the interference fringes as described above, the layer T1 and the layer T2 are dissolved, penetrated, or swollen with each other in the vicinity of the interface I, and the refractive index discontinuity in the vicinity of the interface I is reduced. A technique for relaxing and imparting light scattering properties in the vicinity of the interface is disclosed (for example, Patent Document 2).
For example, when the technique of Patent Document 2 is applied to a two-layer laminate as shown in FIG. 13, when the transparent layer T2 is applied and formed on the surface of the transparent layer T1, the coating for forming the transparent layer T2 is applied. By using a solution that can dissolve (disperse or swell) the transparent layer T1 as a liquid dilution solvent (dispersion medium, unreacted monomer, etc.), the interface between the layer T1 and the layer T2 as shown in FIG. In the vicinity of I, a compatible diffusion layer I _diffused is formed in which the resin of the layer T1 and the resin of the layer T2 are mixed together by dissolution, permeation, or swelling.

In the compatible diffusion layer I _diffused , the discontinuity of the refractive index is also relaxed, and the interface reflected light itself is reduced. Furthermore, light scattering occurs in the vicinity of the layer I _diffused , and the light incident from the interface I into the layer T2 becomes scattered transmitted light I _t ^scatter with reduced coherence. Therefore, no interference fringes are generated in the transmitted light L _OUT .
However, even when the technique of the above-mentioned Patent Document 2 is used, as is clear from FIG. 14, the incident light L can be obtained by the scattered transmitted light I _t ^scatter and the scattered reflected light I _r ^scatter in the compatible diffusion layer I _diffused . There is still a loss of transmitted light (light to be used) for _IN . Moreover, in the technique of patent document 2, the haze may increase due to scattering in the compatible diffusion layer I _diffused . When the image light is transmitted, the transmitted image may be clouded and the sharpness may decrease.

  On the other hand, Patent Document 3 discloses a window material for a display device in which fine irregularities having a specific shape for preventing reflection are formed on the back surface.

Japanese Patent Publication No. 7-51641 Japanese Patent Laid-Open No. 2005-144836 JP 2003-4916 A

  The present invention has been made to solve the above problems, and is a translucent article comprising a laminate of transparent layers including at least one pair of adjacent two layers having different refractive indexes, and has a refractive index of two layers. To provide a translucent article in which reflection loss of transmitted light at the interface between two layers due to a difference and / or interference fringes generated by the interface is eliminated or reduced, and haze does not increase. Objective.

The translucent article according to the present invention is composed of a laminate of transparent layers including at least one pair of adjacent two layers having different refractive indexes, and has fine unevenness at the interface of at least one set of the adjacent two layers. A translucent article,
When the minimum wavelength in the vacuum of the visible light wavelength band is λMIN and the period at the most convex portion of the fine unevenness is PMAX,
PMAX ≦ λMIN
Have the relationship
In addition, when it is assumed that the fine irregularities are cut along a plane orthogonal to the irregular direction, the cross-sectional area occupancy of the transparent layer on the side where the most convex portions are formed in the cross section is the highest from the most convex portions of the fine irregularities. As it goes to the recess, it gradually increases gradually and reaches 100% at the most recess.

  According to the translucent article according to the present invention, the interface between adjacent two layers having different refractive indexes is the fine irregularities of the specific shape, so that the fine irregularities are obtained with respect to the light reaching the interface. This refractive index acts as the average value of the refractive indexes of both media forming the fine irregularities. Accordingly, the discontinuity of the refractive index change at the interface between adjacent two layers having different refractive indexes is alleviated. In a still more preferred form, it changes gradually and continuously. Since light reflection at the material interface occurs due to a discontinuous change in the refractive index, the light reflection at the interface can be eliminated or reduced by making the fine irregularities of the interface specific. . Therefore, reflection loss of transmitted light at the interface between the two layers and / or interference fringes generated by the interface are eliminated or reduced. In addition, when specific fine irregularities having a resolution equal to or lower than the light resolution as described above are formed, the light is not scattered and the haze value does not increase. Furthermore, in the translucent article according to the present invention, the specific fine irregularities are formed inside and are not exposed on the surface, so the fine irregularities are worn over time or filled with concave portions due to oil stains or the like. The above-described effects are not reduced.

  According to the present invention, a translucent article comprising a laminate of transparent layers including at least one pair of adjacent two layers having different refractive indexes, and transmission at the interface between the two layers due to the refractive index difference between the two layers It is possible to provide a translucent article in which reflection loss of light and / or interference fringes generated by the interface are eliminated or reduced, and haze does not increase. Further, the translucent article according to the present invention is one in which the above-described effect does not decrease over time.

The translucent article according to the present invention is composed of a laminate of transparent layers including at least one pair of adjacent two layers having different refractive indexes, and has fine unevenness at the interface of at least one set of the adjacent two layers. A translucent article,
When the minimum wavelength in the vacuum of the visible light wavelength band is λMIN and the period at the most convex portion of the fine unevenness is PMAX,
PMAX ≦ λMIN
Have the relationship
In addition, when it is assumed that the fine irregularities are cut along a plane orthogonal to the irregular direction, the cross-sectional area occupancy of the transparent layer on the side where the most convex portions are formed in the cross section is the highest from the most convex portions of the fine irregularities. As it goes to the recess, it gradually increases gradually and reaches 100% at the most recess.

  According to the translucent article according to the present invention, the interface between adjacent two layers having different refractive indices is the fine irregularities of the specific shape. The refractive index of the fine uneven portion acts as an average value of the refractive indexes of both media forming the fine uneven portion. Accordingly, the discontinuity of the refractive index change at the interface between adjacent two layers having different refractive indexes is alleviated. In a still more preferred form, it changes gradually and continuously. Since light reflection at the material interface occurs due to a discontinuous change in the refractive index, the light reflection at the interface can be eliminated or reduced by making the fine irregularities of the interface specific. . Therefore, reflection loss of transmitted light at the interface between the two layers and / or interference fringes generated by the interface are eliminated or reduced. In addition, when specific fine irregularities having a resolution equal to or lower than the light resolution as described above are formed, the light is not scattered and the haze value does not increase. Furthermore, in the translucent article according to the present invention, the specific fine irregularities are formed inside and are not exposed on the surface, so the fine irregularities are worn over time or filled with concave portions due to oil stains or the like. The above-described effects are not reduced.

  The drawings will be described below with reference to the drawings as appropriate. In any of the drawings, the front and back are the upper side of the drawing, the lower side of the drawing is the back side, and the unevenness protrudes upward when the projection protrudes upward. If you want to make it concave.

FIG. 1 is a sectional view conceptually showing a translucent article 10 according to the present invention. As shown in the figure, the translucent article 10 according to the present invention has the specific fine unevenness at the interface I between the first transparent layer T1 having a refractive index N1 and the second transparent layer T2 having a refractive index N2. P ₁₂ is formed. Incidentally, the specific fine irregularities P ₁₂ is formed at the interface of the transparent layer of two different layers having refractive index in the translucent article 10 according to the present invention. The fine irregularities P ₁₂ present invention unique is the unevenness of the particular shape of the wavelength or less in size of visible light. Such fine irregularities alleviate sudden and discontinuous refractive index changes between two transparent layers with different refractive indices, and even if they are discontinuous, there are few steps in the refractive index, or even more completely It is possible to change the refractive index to a continuous and gradually changing refractive index. The reflection of light is a phenomenon caused by a sudden and rapid change in the refractive index at the material interface, so that the light reflection preventing effect can be obtained by the change in the refractive index that is continuously changed spatially. As a result, the reflection loss of the transmitted light at the interface between the two layers due to the difference in refractive index between the two layers and / or interference fringes generated by the interface are eliminated or reduced. Further, in the translucent article of the present invention, since the fine irregularities are formed not inside the surface but inside the translucent article, the fine irregularities shape becomes dull due to wear or filling of concave parts due to oil stains during use. The effect is not reduced.

The translucent article 10 according to the present invention may be a laminate of three or more transparent layers as shown in FIG. 2, and in that case, as shown in FIG. it only interface I ₂ in between a pair of T2 and T3 layer of different adjacent two layers of refractive index the specific fine irregularities P ₂₃ may be formed, as shown in FIG. 2 (B) As described above, the specific fine concavo-convex shapes P ₁₂ , P ₂₃ , and P ₃₄ may be formed at all the interfaces I ₁ , I ₂ , and I ₃ of the adjacent two layers having different refractive indexes. Furthermore, the translucent article 10 according to the present invention, a set of interface among the different adjacent two layers of refractive index as well as the specific fine irregularities P ₁₂ are formed, in addition to FIG. As shown in FIG. 3 (A), the specific fine concavo-convex shape _Psurf may be formed on the outermost surface (upper side of the drawing) of the laminate, or as shown in FIG. 3 (B). The specific fine concavo-convex shape P _rear may be formed on the back surface (lower side of the drawing), and further, the specific surface may be formed on both the outermost surface and the back surface of the laminate as shown in FIG. Fine uneven shapes P _surf and P _rear may be provided. As described above, the specific fine uneven shape provided on the outermost surface or the rearmost surface causes a continuous and gradually changing refractive index change between the transparent layer and air on the fine uneven surface. It is possible to change to a change in refractive index. Thus, when the above-mentioned specific fine uneven shape is formed also on the outermost surface and / or the outermost surface, the light on the outermost surface and / or the outermost surface is changed by the refractive index change that is spatially continuously changed. It is preferable because an antireflection effect is obtained. In this case, when forming fine irregularities on the outermost back surface where the user may not touch the translucent article, as in the case where the fine irregularities are formed inside, wear during use, The fine uneven shape is not dulled by filling the recesses with oil stains, and the antireflection effect is not lowered.

  In addition, the above illustration does not limit the aspect of the translucent article of this invention. Any device that has substantially the same structure as the technical idea described in the claims of the present invention and that exhibits the same effect can be included in the technical scope of the present invention. .

[Fine unevenness]
4 to 6 are conceptual diagrams for conceptually explaining a preferable form of the refractive index distribution obtained by the specific fine unevenness. First, FIG. 4 shows that one of the adjacent two layers (transparent layer 1A and transparent layer 1B) having different refractive indexes occupies 100% in the space where Z ≦ 0, and Z = 0 A state in which a number of fine irregularities 2 having the Z-axis direction as the irregularity direction is formed on the XY plane is shown. When it is assumed that the fine unevenness 2 is cut on a plane (Z = z) parallel to the XY plane orthogonal to the uneven direction (Z-axis direction), the transparent on the side forming the most convex portion in the cross section The cross-sectional area occupancy of the layer 1A gradually increases from 0% as it goes from the height Z = H _MAX of the most convex portion 2t of the fine unevenness to the most concave portion Z = 0, and the most concave portion Z = 0. At 100%. On the contrary, the other transparent layer 1B formed in the space where Z> 0 has a cross-sectional area occupancy of 0% at the most concave portion Z = 0, and the highest convex portion having fine irregularities from Z = 0. As it goes to the height Z = H _MAX of 2t, it gradually increases from 0% and reaches 100% at the height Z = H _MAX of the most convex portion 2t. The other transparent layer 1B occupies 100% above the most convex part 2t of the fine irregularities, that is, in the space of the portion of H _MAX ≦ Z. In addition, the cross-sectional area occupation rate in 1 A of transparent layers means the total area (occupation area of 1 A of transparent layers / total area) of the part which 1 A of transparent layers occupy with respect to the total area which consists of 1 A of transparent layers and 1 B of transparent layers. In FIG. 5, the cross-sectional area occupancy in the transparent layer 1 </ _b > A corresponds to a region denoted by the symbol na.

In the present invention, when the period of the fine projections 2t is PMAX, the PMAX is equal to or less than the minimum wavelength λMIN in the vacuum of the visible light wavelength band. Even if there is a spatial distribution in the refractive index of the medium (the transparent layer 1A and the transparent layer 1B), the distribution of the light reaching the light reaches a wavelength below the wavelength of interest. Does not act directly on light, but acts as an average. And said average refractive index (also referred to as the effective refractive index) is the cross-sectional area occupying ratio of the transparent layer 1A to the refractive index n _a of the transparent layer 1A (a percentage of the total of the total area of the portion of FIG. 5 reference. Numeral n _a) over, and the total value is multiplied by (percentage of the total of the total area of the reference FIG. parts of the code n _b) cross-sectional area occupying ratio of the transparent layer 1B to the refractive index n _b of the transparent layer 1B. That is, if the cross-sectional area occupying ratio of the fine convexo-concave portion is a continuous variation over the top recess from the most projecting portion, the average refractive index toward the n _b toward the outermost recess from the most projecting portion to n _a the continuous change (See FIG. 6). In the interface of the transparent layers having different refractive indexes according to the present invention, the refractive index after being averaged (effective refractive index) is distributed so as to change continuously as the light travels. It can prevent reflection. In the present invention, the period PMAX in the most convex part 2t is the maximum distance among the distances between the most convex parts 2t of the adjacent fine irregularities 2, and each fine irregularity is regularly arranged and has periodicity. The distance between adjacent fine irregularities may be the same, but it may be a structure having no periodicity and uneven distance between adjacent fine irregularities. When the distances between adjacent fine irregularities are not uniform, the distance between the largest fine irregularities is defined as PMAX.

The above will be described in more detail based on the drawings. In FIG. 4, light enters from the direction of the transparent layer 1B (positive on the Z axis) to the direction of the transparent layer 1A (negative on the Z axis), travels through the transparent layer 1B, and the transparent layer 1B and the transparent layer It is assumed that the vicinity of the interface of 1A is proceeding in the negative direction of the Z axis, and the Z axis coordinate is exactly located at z. Then, for the light at Z = z here, the refractive index of the medium is strictly defined by an XY plane (transverse section: horizontal) orthogonal to the Z axis at Z = z because the transparent substrate has specific fine irregularities. It appears to have a distribution f (x, y, z) within the cross section. That is, in the XY plane, cross section of the transparent layer 1A has a refractive index n _a, other portions, the portion of the specific transparent layer 1B is the refractive index n _b (see FIG. 5). However, in practice, for light, the refractive index distribution on a spatial scale smaller than the wavelength (the wavelength of light related to visual recognition of the display device has a distribution, the minimum wavelength λMIN of the wavelength band) is averaged. As a result, the effective refractive index (average refractive index) of the averaged result is obtained by integrating the refractive index distribution f (x, y, z) in the XY plane in the XY plane, It becomes. As a result, the distribution of the effective refractive index (n _ef ) is a function n _ef (z) of only z (see FIG. 6).

Therefore, if the area of the convex portion of the transparent substrate in the fine irregularities is a shape that continuously increases toward the concave portion, the portion of the transparent layer 1A and the portion of the transparent layer 1B in the XY plane Since the area ratio continuously changes in the Z-axis direction, the effective refractive index n _ef (z) is a continuous function with respect to z.
On the other hand, from a medium of refractive index n _0, consider the case where light enters a medium of refractive index n _1. For the sake of simplicity, consider an incident angle θ = 0 ° (normal incidence). However, the incident angle is an angle with respect to the normal of the incident surface. In this case, the reflectance R at the medium interface does not depend on the polarization and the incident angle, and is expressed by the following formula (2).

Therefore, the fact that the (effective) refractive index change in the Z direction is a continuous function means that the refractive index at Z = z is n ₀ , two points separated by a small distance Δz in the Z direction (light traveling direction). When the refractive index at Z = z + Δz is n ₁ , if Δz → 0, then n ₁ → n ₀ (from the definition of the continuous function), and therefore R → 0 from equation (2).

  Strictly speaking, the wavelength of light in the object is λ / n where λ is the wavelength in the vacuum and n is the refractive index of the object, and is generally somewhat smaller than λ. . Therefore, if the condition of PMAX ≦ λMIN is designed using the wavelength in vacuum, at least the refractive index of any of the adjacent two-layer media 1A and 1B is the refractive index in vacuum (refractive index = 1, any medium). The above antireflection effect is exhibited only when it is equal to the lowest possible refractive index). That is, this case gives an upper limit value of PMAX that can be obtained depending on the medium.

  In most ordinary media, the refractive index n is larger than the refractive index of vacuum. Strictly speaking, the PMAX condition for preventing reflection is PMAX ≦ λMIN / n (≦ λMIN), and the above-mentioned vacuum wavelength is If the upper limit of the inequality used is used, a part deviating from the antireflection condition occurs in some low wavelength regions. However, even in that case, although not perfect, a certain degree of antireflection effect can be achieved. That is, even when the refractive index n of the medium is larger than the refractive index of the vacuum, PMAX ≦ λ / n for light in a sufficiently long wavelength region having a wavelength λ where λ / n ≧ λMIN. This is because the above condition is satisfied. Further, this is because an antireflection effect can be expected although it is a little for light satisfying PMAX ≧ λ / n.

  However, of course, when the refractive index n of the medium is larger than the refractive index of the vacuum, if it is necessary to set a numerical value more strictly and complete the antireflection effect, the adjacent surface having the fine unevenness at the interface. Of the refractive indexes of the two transparent layers, it is preferable to set so that PMAX ≦ λMIN / n ′, where n ′ is a large refractive index. Since the material used for the transparent layer, such as glass and acrylic resin, usually has a refractive index of around 1.5, the wavelength (λ / n ′) in the transparent substrate having a refractive index n ′ is about 0.7λ. Become. Specifically, when λMIN is the lower limit of the visible light wavelength band of 380 nm and n ′ is 1.5, λMIN / n ′ may be 250 nm, that is, PMAX may be 250 nm or less.

  Next, as for the shape of the fine unevenness, the cross-sectional area occupation ratio of the transparent layer on the side forming the most convex portion in the cross section when it is assumed that the fine unevenness is cut by a plane perpendicular to the uneven direction is Any shape may be used as long as it gradually increases gradually from the most convex part of the fine unevenness to the most concave part and becomes 100% in the most concave part. For this purpose, at least a part of the ridges of the fine unevenness may have an inclined slope, and even in the case of the fine unevenness 2G having a vertical side face with the inclined face as shown in FIG. good. In particular, preferably, the cross-sectional area occupancy of the transparent layer on the side of forming the most convex part at the most convex part continuously converges to 0%, and the cross-sectional area occupancy at the most concave part continuously to 100%. A convergent shape. Specifically, for example, shapes as shown in FIGS. 7A to 7G can be mentioned.

  However, although the micro unevenness in the present invention is not illustrated, the cross-sectional area occupancy continuously changes on the slope portion, for example, the vertical cross-sectional shape is a trapezoid in which the convex portion is narrowed, and the most convex portion Or the most concave part may be a flat shape. In this case, the cross-sectional area occupation ratio of the transparent layer on the side where the most convex part is formed is not completely 0% (for example, 20%) in the cross-sectional area in the most convex part. As it goes to the most concave portion, it gradually increases, for example, from 20% to 80%, and when it reaches 100% at the most concave portion, it changes discontinuously from, for example, 80% to 100%. The cross-sectional area occupancy of the transparent layer on the side where the most convex portions are formed also changes discontinuously from 20% to 0%, for example, on the most convex portions and the uppermost portions of the most convex portions. However, even in this case, a certain degree of effect can be obtained. That is, in this case, reflection occurs in the most convex part and the most concave part, but the cross-sectional area occupancy continuously changes in the slope part, so that the antireflection mechanism is effective. The shape of the fine irregularities of the present invention may be any shape as long as such conditions are satisfied. Accordingly, the slope of the fine irregularities 2 may be a straight line or a curved line, a broken line, or a combination of these as long as it has a vertical cross-sectional shape.

Further, the effective refractive index n _ef (z) as a function of the Z direction from the air into the substrate, in order to as continuously changes from n _a to n _b is the side that forms the outermost protruding portion 7A or 7C where the cross-sectional area occupancy converges to 0% at the most convex part of the fine irregularities of the transparent layer [that is, the most convex part is a point (in three-dimensional space A shape that becomes a point or a line if captured) and a shape in which the cross-sectional area occupation ratio continuously converges to 100% in the most concave portion is most preferable.
And as a more preferable shape of the shape of the fine unevenness | corrugation 2, the sharpness of the peak and trough is prescribed | regulated. That is, as conceptually shown in the vertical sectional view of FIG. 8A, the shape 2 _{Mt of the} mountain side Mt having the most convex portion 2t of the fine unevenness 2 is the shape of the valley side Mb having the most concave portion 2b. Compared to 2 _Mb , the shape is sharper. In addition, the boundary which bisects the fine unevenness | corrugation 2 into the peak side Mt and the valley side Mb is the height H (most convex part 2t) of the fine unevenness | corrugation 2 as conceptually shown with the (vertical) sectional drawing of FIG. 8 (A). With respect to the difference in height from the most concave portion 2b), the height H / 2 is exactly half, and the portion above the height H / 2 is regarded as the mountain side Mt, and the portion below the height H / 2 is regarded as the valley side Mb.

And the peak side Mt is more “pointed shape” than the valley side Mb. Compared to a neutral shape in which the peak side and the valley side are the same shape in a vertical section, such as a simple sine wave shape or a triangular shape, It is a pointed shape. Here, if the fine unevenness 2 is conceptually shown in a vertical section when it is assumed that the fine unevenness 2 is cut along a plane parallel to the unevenness direction, the shape will be further described with reference to FIGS. 8 (A) and 8 (B). As shown in FIG. 8 (A), the shape 2 _{Mt of the} mountain side Mt having the most convex portion 2t of the fine unevenness 2 that is a portion having a height H / 2 or more and the most concave portion 2b that is a portion having a height H / 2 or less. the shape 2 _Mb of valley Mb having, in the upside down shape 2 _Mb of the valley as shown in FIG. 8 (B), when compared with those shapes overlapping the shape 2 _Mt mountain side, they are completely The width Wt at the height H / 2 of the mountain-side shape 2 _Mt is smaller (narrower) than the width Wb at the height H / 2 of the valley-side shape 2 _Mb , and Wt <Wb. Applicable shape. The sharpness of the shape is considered to be the portion occupied by the material portion of the transparent layer 1A on the side forming the most convex portion in the shape 2 _{Mt on the} mountain side Mt, and adjacent to the transparent layer 1A in the shape _Mb on the valley side Mb. Consider the portion occupied by the transparent layer 1B. In other words, the shape of the mountain and the valley are different.
In the pointed shape, the shape formed by the most convex portion 2t or the most concave portion 2b is a vertices such as a vertex (see, for example, a cone or a quadrangular pyramid in a three-dimensional space) [see FIG. 7C]. In addition to an acute-angled shape having a curved shape, a curved shape having a rounded curvature as shown in FIGS. 8A and 7A is also included. Therefore, in the combination of the shape of the most convex part and the most concave part of the fine unevenness, when both the most convex part and the most concave part have cusps, or both have a curvature, either one has a cusp and the other has a curvature. Any case is acceptable.

  As described above, in the present invention, even if the period and the height, which are the size elements of the fine unevenness, are the same, the shape of the fine unevenness is changed to the shape of the peak side having the most convex portion as described above. By making the shape sharper than the shape on the valley side, the light reflectance can be made smaller. For example, in the fine unevenness 2A as shown in FIG. 7A corresponding to the present invention, the antireflection effect is more effective than the fine unevenness 2B having a neutral shape with the same sharpness on the mountain side and the valley side as shown in FIG. 7B. Becomes larger.

  In FIGS. 7A and 7B, the vertical cross-sectional shape of the fine irregularities is a comparison with a waveform having only a curve such as a sine wave, but the cross-sectional shape is triangular (a more sharp shape). In order to do this, if the slope is composed only of straight lines, the slope is composed of at least two straight lines, so it is not strictly a triangle, but it is a triangle-like shape as a whole, so it is a “triangle”. The same applies to the case of fine irregularities. That is, the fine unevenness 2C having a shape in which the peak side is pointed more than the valley side as shown in FIG. 7C, and the fine unevenness 2D in which the peak side and the valley side have the same sharpness shape as shown in FIG. On the contrary, when comparing the fine unevenness 2E having a shape in which the valley side is sharper than the mountain side as in (E), the fine unevenness 2C has the smallest reflectance, and the fineness unevenness 2C has the smallest reflectance. The relationship of unevenness 2C <fine unevenness 2D <fine unevenness 2E is established.

  Further, in the fine unevenness according to the present invention, the vertical cross-sectional shape is a shape in which the peak side is sharper than the valley side as shown in FIGS. 7A and 7C in the vertical cross-section in all directions of the horizontal plane. Is the most effective and preferred. However, if they form the main body and only in some directions, they have the same sharpness on the mountain side and valley side, or the shape on which the valley side is sharp, as shown in FIG. 7D or 7E. Even if you do it, you can get a reasonable effect.

  Here, FIG. 9 shows an enlarged cross-sectional view of the fine irregularities of FIGS. 7 (C) to 7 (E). In FIG. 9, the fine unevenness 2C corresponds to FIG. 7C, the fine unevenness 2D corresponds to FIG. 7D, and the fine unevenness 2E corresponds to FIG. 7E. The shape connecting the most convex portions 2t and the most concave portions 2b of each fine unevenness with a straight line is the fine unevenness 2D that is a neutral shape. Then, at the height H / 2 with respect to the height of the fine unevenness, the fine unevenness 2C in which the peak side corresponding to the present invention is pointed from the valley side has a width Wt on the peak side of the neutral fine unevenness 2D. The inner side (base material side) is smaller than the width. Conversely, the fine unevenness 2E with the valley side sharper than the mountain side has a width Wt on the mountain side that is larger than the width on the mountain side of the neutral fine unevenness 2D (outside the space).

  In addition, the horizontal cross-sectional shape of each fine unevenness | corrugation is arbitrary, such as circular (for example, FIG. 4), an ellipse, a triangle, a quadrangle, a rectangle, a hexagon, and other polygons. Further, the horizontal cross-sectional shape does not have to be the same (similar shape) from the most convex part to the most concave part of the fine irregularities. Therefore, for example, when the horizontal cross-sectional shape is circular and the vertical cross-sectional shape is an isosceles triangle, the three-dimensional shape of the fine unevenness is conical, and the horizontal cross-sectional shape is circular and the vertical cross-sectional shape is triangular. The three-dimensional shape of the fine irregularities is an oblique cone, and the three-dimensional shape of the fine irregularities is a triangular pyramid when the horizontal cross-sectional shape is triangular and the vertical cross-sectional shape is a regular triangle. In the case where is triangular, the three-dimensional shape of the fine irregularities is a quadrangular pyramid. In addition, as described above, for example, the isosceles triangle “shaped” in the above is, for example, that the most convex portion is sharper than the isosceles triangle as shown in FIGS. 7C and 7F. A shape similar to an isosceles triangle.

  In addition to the two-dimensional arrangement of the fine irregularities in the horizontal plane as illustrated in FIG. 4, primary irregularities such as the linear groove-shaped fine irregularities 2 illustrated in the perspective view of FIG. The original arrangement may be used, and both are effective. However, in the case of the one-dimensional arrangement, anisotropy occurs in which a direction in which an antireflection effect is obtained and a direction in which the antireflection effect is not obtained are generated in relation to the amplitude direction of the light wave. Therefore, the two-dimensional arrangement illustrated in the perspective view of FIG. 4 and the plan views of FIGS. 10B and 10C is preferable in that there is no directivity.

  Further, as illustrated in the plan view of FIG. 11, when the fine irregularities 2 are two-dimensionally arranged in the horizontal plane, the transparent layer 1 </ b> A is adjacent to the transparent layer 1 </ b> B out of the two adjacent layers based on a certain horizontal plane. Convex-facing mountain side Mt and the space occupied by the transparent layer 1B are convex toward the transparent layer 1A (that is, the transparent layer 1A part is concave toward the transparent layer 1A side, and the valley turns the mountain upside down. The fine irregularities 2 may be arranged in a double lattice pattern in which the valley side Mb is alternately intertwined. In FIG. 11, the horizontal cross-sectional shapes of the mountain side Mt and the valley side Mb are drawn with a contour line Lt and a contour line Lb, respectively. A plurality of concentric contour lines Lt represent the mountain side Mt, and a plurality of concentric dotted contour lines Lb represent the valley side Mb. In the case of fine irregularities such that such a mountain and a valley like a mountain turned upside down are alternately arranged, the top part of the mountain is the most convex part 2t of the fine irregularity, and the valley bottom part of the valley is It becomes the most concave portion 2b having fine irregularities. In the figure, the part indicated by the symbol Mc is a heel part having a shape like a heel or a horse heel. Further, in the figure, the contour lines are only for indicating the arrangement of peaks and valleys, and do not indicate that an actual certain contour line is exactly as illustrated. In addition, such fine unevenness is also a kind in the case where the above-described two-dimensional arrangement on the horizontal plane in FIG. 10B is performed with the fine unevenness having a conical shape (a valley is formed between the cones). It is formed).

  In addition, as for the fine unevenness | corrugation by this invention as mentioned above, although the solid shape of each fine unevenness | corrugation (or peak and valley) may be the same, it does not need to be the same. Further, when the individual fine irregularities 2 are two-dimensionally arranged, the period may be the same in each fine irregularity or not all.

Further, the height H of the fine irregularities is determined according to the desired reflectance reduction effect and the maximum wavelength of the visible light band incident on the substrate surface. Usually, the height H is the minimum height H _MIN and is about 100 to 1000 nm. However, according to the fine irregularities peculiar to the present invention, according to the conventional concept described in Japanese Patent Application Laid-Open No. 50-70040, etc., the height H is such that it is difficult to obtain an antireflection effect below the wavelength of light. Even so, the antireflection effect at the interface can be obtained. For example, even when the minimum height H _MIN is 250 nm, good antireflection performance at the interface can be obtained.
Here, as an example of the specific shape and size of the fine irregularities, the shape is an aggregate of two-dimensional regular arrangements of many conical shapes whose vertical cross section is sinusoidal and whose horizontal cross section is circular. And the period P _MAX is 50 to 450 nm and the minimum height H _MIN is 1.5 times the period P _MAX .

(Transparent layer)
As the transparent layer used in the present invention, various materials can be used depending on applications, and materials having mechanical strength are usually used, but there is no particular limitation. Here, the transparent layer only needs to have a property of transmitting light, and it can be a guide that haze is 5% or less and total light transmittance is 60% or more. However, in the present invention, it is premised that the adjacent two transparent layers on which the fine irregularities of the specific shape are formed at the interface have different refractive indexes. The refractive index difference between the two layers so that the generation of interference fringes and reflection loss as described above cannot be ignored is about 0.07 or more. In particular, when the refractive index difference between the two layers is 0.14 or more, the generation of interference fringes and reflection loss are particularly large and become conspicuous. By applying the present invention, more effective effects can be obtained. It is done.

  The material used for the transparent layer is not particularly limited. For example, poly (meth) methyl acrylate, poly (meth) ethyl acrylate, methyl (meth) acrylate- ( Acrylic resin such as meth) butyl acrylate copolymer [However, (meth) acryl means acryl or methacryl. ], Polypropylene, polymethylpentene, cyclic olefin polymers (typically norbornene resins, etc., for example, the product name “ZEONOR” manufactured by ZEON CORPORATION, “ARTON” manufactured by JSR Corporation, etc. Polyolefin resins, polycarbonate resins, polyethylene terephthalate, polyethylene naphthalate, and other thermoplastic polyester resins, polyamide resins, polystyrene, acrylonitrile-styrene copolymers, polyether sulfone, polysulfone, cellulose resins, vinyl chloride resins , Polyether ether ketone, thermoplastic resins such as polyurethane, or glass (including ceramics).

  In addition, an ionizing radiation curable resin that is usually used as a binder component in order to form a layer that imparts another function adjacent to a transparent layer that is normally used as a transparent substrate as described above. A composition and / or a thermosetting resin composition can also be preferably used.

  The ionizing radiation curable resin composition has a curing reactivity that causes a reaction that causes polymerization or dimerization to proceed directly when irradiated with ionizing radiation or indirectly by the action of an initiator. Monomers, oligomers and polymers having functional groups can be used. Specifically, radically polymerizable monomers and oligomers having an ethylenically unsaturated bond such as (meth) acryloyl group, vinyl group, allyl group and the like are preferable, and one molecule is formed so that cross-linking occurs between molecules of the binder component. It is desirable that it is a polyfunctional binder component having two or more, preferably three or more curing reactive functional groups. When it has an ethylenically unsaturated bond, photocuring can be caused directly or indirectly by the action of an initiator by irradiation with ionizing radiation such as ultraviolet rays or electron beams. The handling including the process is relatively easy. Among these, a (meth) acryloyl group is preferable because of excellent productivity. However, other ionizing radiation curable binder components may be used. For example, a photocationically polymerizable monomer or oligomer such as an epoxy group-containing compound may be used.

  The ionizing radiation curable resin composition is preferably one having an acrylate-based functional group, such as a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, It comprises an ionizing radiation curable resin containing a polybutadiene resin, a polythiol polyene resin, an oligomer or prepolymer such as a (meth) acrylate of a polyfunctional compound such as a polyhydric alcohol, and a reactive diluent. Examples of the reactive diluent include monofunctional monomers such as ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene, vinyltoluene, and N-vinylpyrrolidone, and polyfunctional monomers such as trimethylolpropane tri (meth). Acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanedione It is done.

  When the above ionizing radiation curable resin is used as an ultraviolet curable resin, as a photopolymerization initiator in the binder, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime esters, thioxanthones, As a sensitizer, n-butylamine, triethylamine, tri-n-butylphosphine and the like can be mixed and used. In particular, in the present invention, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer. Various examples of photopolymerization initiators are also described in the latest UV curing technology (P.159, publisher: Kazuhiro Takasawa, publisher; Technical Information Association, Inc., published in 1991). Photopolymerization initiators can also be used in the present invention. Preferable examples of commercially available photocleavable photoradical polymerization initiators include Irgacure 651, Irgacure 184, and Irgacure 907 (each trade name) manufactured by Ciba Specialty Chemicals.

  On the other hand, as a thermosetting resin, a monomer having a curing reactive functional group that can be cured by heating to promote a large molecular weight reaction such as polymerization or crosslinking with the same functional group or another functional group. Oligomers and polymers can be used. Examples of the thermosetting resin include monomers and oligomers having an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, a hydrogen bond forming group, and the like. Specifically, as the thermosetting resin, phenol resin, urea resin, diallyl phthalate resin, melanin resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, Silicon resin, polysiloxane resin or the like is used. These thermosetting resins are used by adding a curing agent such as a crosslinking agent and a polymerization initiator, a polymerization accelerator, a solvent, a viscosity modifier and the like as necessary.

In addition, the transparent layer in the present invention may be formed by using one or more of the above-mentioned thermoplastic resins, ionizing radiation curable resin compositions and / or thermosetting resin compositions. good.
In addition, the shape of a transparent layer can have various shapes by the use of a translucent article. For example, although it is a conceptual diagram, it has a flat plate shape as illustrated in FIG. In the case of a flat plate shape, there may be a flexible sheet shape. That is, the mechanical strength is not limited to being rigid. The transparent layer may be a three-dimensional solid object. That is, the shape of the translucent article may be a three-dimensional solid object. For example, when the window material of the display unit is exemplified, the antireflection surface portion has the flat plate shape, but includes an object having a shape for attaching the window material such as a rib around it. In addition, as a specific example of the thickness when the substrate is flat, it is usually about 0.5 to 2 mm in applications such as a window material of the display unit.

  In addition, although the fine unevenness | corrugation 2 comprises a part of transparent layer, the transparent layer containing this fine unevenness | corrugation 2 is the same also including a fine unevenness | corrugation part like the translucent article 10 illustrated in FIG. In addition to being configured as a continuous object made of a material, as shown in the translucent article 10 illustrated in FIG. 12, a portion including the fine unevenness 2 (fine unevenness layer 11) and a portion not including the fine unevenness (transparent layer base) For example, a structure in which two layers made of the material 12) are in close contact with each other may be used.

[Production method of fine irregularities]
The method for forming the fine irregularities 2 at the interface between two adjacent transparent layers is not particularly limited in the present invention, and a method for forming fine irregularities on a conventionally known lens or the like can be used as appropriate.
Examples of the method for forming the first transparent layer include the following (1) to (7).
(1) First, a photoresist film formed on the surface of an object such as glass is exposed to interference fringes using a laser interference method used for producing holograms, diffraction gratings, etc. After forming the density and developing, the object may be etched in the presence of the photoresist film to produce fine irregularities on the object surface, and may be used as the first transparent layer. Alternatively, an object on which the fine irregularities are formed is used as a mold, and a photo-curing resin is applied to this mold (or the mold may be used as a prototype, and then a replica mold may be prepared once by plating or the like). The first transparent layer is formed by replicating desired fine irregularities on the surface of the resin layer by using a 2P method (photo-polymerization method) for photocuring and a resin injection molding method or the like (Japanese Patent Laid-Open No. 2003-149405). Issue gazette).

(2) After a metal thin film layer such as aluminum is formed on the surface of an object such as glass by a thin film forming means such as vapor deposition, the metal thin film layer is treated with water under heating to convert it into an oxide or hydroxide. Thus, desired fine irregularities are formed on the surface of the metal thin film layer (see Japanese Patent Publication No. 61-48124). Further, if necessary, the metal thin film layer surface is used as a mold or, for example, a replica mold is prepared by plating as in (1) above, and this is used as a mold. The first transparent layer is formed by replicating the fine irregularities.

(3) The surface of an object such as glass is appropriately combined with an acid, alkali, organic solvent treatment or the like before and after that, and is subjected to low-temperature plasma treatment to produce desired fine irregularities on the surface (Japanese Patent Laid-Open No. 3-2801). reference). Furthermore, if necessary, the object surface is used as a mold, or, for example, a replica mold is prepared by plating as in (1) above, and this is used as a mold. To form a first transparent layer.

(4) On the surface of an object such as glass, by fixing fine particles having a particle size equal to or smaller than the light wavelength by a dip coating method or the like, forming a fine particle layer of at least one particle layer (preferably one particle layer) A method for producing desired fine irregularities using fine particles (see Japanese Patent Application Laid-Open No. 2002-6108). A weak force such as electrostatic interaction can be used for fixing the object surface and the fine particles. This is because it is a nanometer-order fine particle and can be fixed even with a weak force. Further, if necessary, the surface on which the fine irregularities are formed is used as a mold, or a replica mold is prepared on the mold surface by, for example, plating as in (1) above, and this is used as a mold. Desired fine irregularities are replicated on the surface of the resin layer to form a first transparent layer.

To further explain the formation method of (4) above, in order to fix the fine particles on the object surface in a single particle layer or even in the case of multiple particle layers with a uniform number of particles as much as possible, before the fine particles are brought into contact with the object surface, Preferably, the surface is pretreated. As the pretreatment, for example, a monomolecular film or the like and a polymer electrolyte membrane thinner than the fine particle diameter are formed. As the polymer electrolyte, cationic polymers such as polyethyleneimine quaternized products and polydiallyldimethylammonium chloride, anionic polymers such as sodium polystyrene sulfonate and sodium poly (meth) acrylate are used. The polymer electrolyte membrane may be a single polymer electrolyte monolayer, but more preferably a multilayer membrane in which two or more polymer electrolytes having different polarities are laminated is more desirable in terms of uniform particle number thickness. . As a method for forming such a polymer electrolyte multilayer film, a known alternating adsorption film manufacturing method (for example, Gero Decher et al., Science, vol. 277, p1232, 1997) can be used. This method uses a dipping method to immerse an object alternately in an aqueous cation polymer solution and an aqueous anionic polymer solution to form a polymer electrolyte multilayer film on the surface of the object by controlling the film thickness on the order of nanometers.
When it is desired to enhance the fixing force of the fine particles on the object surface, for example, the object surface after the fine particles are fixed may be covered with a resin layer. The resin layer can be effective even with a monomolecular layer. Moreover, the polymer electrolyte as described above can be used for the resin, and the dipping method as described above can be used for the layer formation.
In addition, if the dipping method is used as described above, an endless fine uneven surface can be formed when the object to be formed by the dipping method is a continuous belt-like sheet (film), which is preferable in terms of productivity. Moreover, the said sheet | seat can also be manufactured as a transparent layer.

(5) Using the method described in the above (1) to (4), an embossed plate formed by forming fine irregularities on a cylinder or flat plate made of metal or the like is prepared. On the other hand, a thermoplastic resin made of acrylic resin, polycarbonate resin, pothiester resin, polystyrene, polyolefin resin, cellulosic resin, etc. is formed by a known melt extrusion method, casting method, calendar method, etc., and the first transparent A layer substrate is formed. Using a known embossing method, the fine irregularities are formed on the first transparent layer substrate using the embossed plate. That is, the first transparent layer substrate is heated and softened to an appropriate temperature between the softening temperature and the melting point. Next, the fine uneven surface of the embossed plate is pressed onto the first transparent layer base to shape (mold) the surface of the first transparent layer into the fine uneven shape, and the first transparent layer is formed. Cool and fix the shaped shape. Thereafter, the embossed plate is released to form a first transparent layer having fine irregularities.

(6) Using the method described in (1) to (4) above, an embossed plate formed by forming fine irregularities on a cylinder or flat plate made of metal or the like is prepared. Meanwhile, the first transparent layer is prepared. In this case, the first transparent layer may be a film formed of the same thermoplastic resin as in the above (5), may be a thermosetting resin having no embossing suitability, or may be glass or ceramics. Next, an emboss receiving layer made of a transparent resin is formed on the first transparent layer. The embossing-receiving layer is a thermoplastic resin having embossing suitability and is formed by selecting and using a resin having the same refractive index as that of the first transparent layer. This is to prevent light reflection at the interface between the embossing receiving layer / transparent substrate layer. Then, in the same manner as in the above (5), the fine irregularities are formed on the emboss receiving layer using a known embossing method to form a first transparent layer.

(7) Using the method described in (1) to (4) above, an embossed plate formed by forming fine irregularities on a cylinder or flat plate made of metal or the like is prepared. As in (6) above, a first transparent layer is prepared. Next, a liquid composition containing an ionizing radiation curable resin is applied onto the first transparent layer to form an emboss receiving layer. The liquid composition is appropriately selected from the above-mentioned various (meth) acrylate-based and epoxy-based monomers, prepolymers, and the like. On the surface of the liquid composition on the first transparent layer, the fine uneven surface of the embossed plate is overlapped and pressed, and the liquid composition is filled and shaped into the fine uneven shape, and in this state, The liquid composition is irradiated with ionizing radiation to crosslink and cure. Here, the ionizing radiation is normally transmitted from the first transparent layer side to reach the liquid composition, but when the embossed plate is transparent to the ionizing radiation, irradiation from the embossed plate side is also performed. Is possible. As ionizing radiation, electromagnetic waves such as ultraviolet rays, X-rays and visible rays, or charged particle beams such as electron beams and ion beams are used. Thereafter, the embossed plate is released to form the fine unevenness on the surface of the embossing receiving layer made of a cured product of ionizing radiation curable resin.

  As a method of forming the second transparent layer after forming the first transparent layer having the specific fine irregularities by using the methods (1) to (7) above, first, A liquid resin composition for the second transparent layer, which is made of a material having a refractive index different from that of the transparent layer after solidified film formation, is prepared. The liquid resin composition comprises a resin-containing solution, dispersion, or unpolymerized monomer or prepolymer. The liquid resin composition includes one or two of a thermoplastic resin such as an acrylic resin, a thermosetting resin such as a urethane resin and an epoxy resin, and an ionizing radiation curable resin such as an acrylate type that is cured by ultraviolet rays or an electron beam. More than one species can be appropriately selected and used. Then, the liquid resin composition for the second transparent layer is applied on the surface of the first transparent layer obtained above to form the fine irregularities, and the fine irregularities are filled. Thereafter, the liquid composition is solidified by drying of a solvent or a dispersion medium, polymerization (including a crosslinking reaction), or the like to form a second transparent layer.

  The fine irregularities can be directly formed on each of the already tangible substrates as in the method (1) above, but translucent light that requires mass production as an industrial product. In the case of a functional article, in consideration of industrial productivity and cost, it is preferable to prepare a shaping mold and form fine irregularities by shaping with this shaping mold. Furthermore, as the shaping mold, a replica mold produced by performing a duplication process by mold taking / reversing once or twice from the original mold is used without using the original mold formed with the fine uneven shape first. preferable. In other words, after first producing a prototype (also referred to as a master plate or a mother plate), a duplication operation for creating a replica mold from this master mold is performed once or twice or more, and the result is obtained. It is preferable to use a duplicated mold (this is also called a main plate or a master plate) as a shaping mold. By using such a shaping mold, the method is excellent in industrial productivity, cost, and the like. For example, even if the main plate is damaged, the main plate can be easily remade.

[Use of translucent article]
The translucent article of the present invention can have any shape such as a three-dimensional shape, a plate, a sheet, and the use is not particularly limited. Applications to which the present invention can be applied are not limited to the applications exemplified below. In particular, the translucent article according to the present invention eliminates or reduces the reflection loss of transmitted light at the interface between the two layers due to the difference in refractive index between the two layers and / or interference fringes generated by the interface, and Since haze does not increase, it is preferable to use it in a place where transmitted light is used.

  For example, the window material of the information display part in various apparatuses, such as a mobile phone, is mentioned. In these information display units, a resin window material such as a plate or a molded product is arranged on the front surface of a display panel such as an LCD. The translucent article as a window material is exposed to the outside, so that it does not have fine irregularities peculiar to the present invention in terms of resistance to scratches and dirt, and the interface between adjacent two transparent layers having different refractive indexes inside the article. In addition, it is preferable that the fine irregularities be provided on the back side of the window material.

  Specific examples of the layer structure of the window material include a case of a laminate of two transparent layers in which a hard coat layer is laminated on a transparent substrate. In this case, since the transparent substrate is usually made of a thermoplastic resin and the hard coat layer is often made of an ionizing radiation curable resin composition, the refractive index difference between the transparent substrate and the hard coat layer is particularly large. There are many cases. Therefore, in the translucent article which has the said layer structure, the said specific fine unevenness | corrugation is provided in the interface of a transparent base material and a hard-coat layer.

In addition to a display panel such as an LCD, the information display unit may be displayed by mechanical means such as a mechanical analog meter represented by a watch, or may be a window material of these. Note that the window material has a flat plate shape, but some have a projection or the like around it from the viewpoint of assembly or design.
In addition to mobile phones and watches, devices having an information display unit with windows as described above include personal computers, PDAs such as electronic notebooks, portable information terminals, calculators, CD players, DVD players, Various portable music players such as MD players and semiconductor memory music players, video tape recorders, IC recorders, video cameras, digital cameras, label printers and other electronic devices, electric rice cookers, electric pots, washing machines, etc. There are electrical products.

Furthermore, transparent materials, such as a transparent plate used for a transparent touch panel etc., are mentioned as a plate-shaped or sheet-shaped translucent article.
The transparent touch panel is, for example, a PDA such as an electronic notebook or a portable information terminal (equipment), a car navigation system, a POS (point-of-sale information management) terminal, a portable order input terminal, an ATM (automatic cash deposit payment combined use) Machine), facsimile, fixed telephone terminal, mobile phone, digital camera, video camera, personal computer, personal computer display, television receiver, television monitor display, ticket vending machine, measuring instrument, calculator, electronic musical instrument, etc., photocopying Used in office machines such as machines, ECR (cash registering machines), or electrical products such as washing machines and microwave ovens.

  Moreover, various optical elements etc. are mentioned as a use of the translucent article of this invention. For example, a camera lens, a camera finder window material, a spectacle lens, an overhead projector Fresnel lens, an optical sensor light input window, a telescope lens, or an optical disk pickup lens such as a CD or DVD, a laser device Output window, and the like.

Furthermore, the use of the translucent article of the present invention includes constituent members of various surface plates of an image display device. Examples of the image display device include a cathode ray tube (CRT, cathode ray tube), a plasma display panel (PDP), a liquid crystal display device (LCD), and an electroluminescent element (EL). Further, as the surface plate, in addition to a protective plate for mere reinforcement, an optical filter that absorbs or reflects a specific wavelength band of ultraviolet light, infrared light, or visible light, an electromagnetic wave shielding filter, an anti-reflection filter, and the like can be given. It is done.
Moreover, as a use of the translucent article of this invention, the window material of various buildings may be sufficient.

Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.
<Example 1>
(1) Formation of fine irregularities in the first transparent layer A transparent biaxially stretched PET film (refractive index: 1.66, Toyobo Co., Ltd .; Cosmo Shine A4100) having a thickness of 100 μm, one surface of which is easily adhered, is 160 ° C. And embossed on the surface not subjected to easy adhesion treatment to form fine irregularities.
The embossed plate was produced as follows. A photomask substrate having a metal chromium film formed on one surface of a synthetic quartz of 152.4 mm (6 inches) square and 6.35 mm thick was prepared, and a positive type EB resist [trade name “ZEP7000” was formed on the metal chromium film. ”(Manufactured by Nippon Zeon Co., Ltd.)] to form a resist layer, followed by drawing with mesh-like drawing data having a vertical and horizontal period of 325 nm using an electron beam drawing apparatus, and using a predetermined developer Development processing was performed. As a result, a resist pattern layer in which an area corresponding to the mesh opening area of the drawing data was opened by development was formed. Next, the metal chromium film exposed from the opening of the resist pattern layer was dry-etched using a chlorine-based gas to open the metal chromium film. A dry etching apparatus “VERSALOCK 7000” manufactured by Unaxis was used for dry etching of the chromium metal film. Next, the resist pattern layer and the metal chromium film are used as an etching resistant layer, and the substrate is dry-etched using a fluorine-based gas to form a desired fine concavo-convex shape in which the peak side of the convex portion is sharper than the valley side of the concave portion. A prototype (mother version) was obtained. Note that “MEPS-6025D” manufactured by Nippon Vacuum Co., Ltd. was used for dry etching of the substrate. Next, a sheet-like replica mold (master plate) made of a nickel-plated plate having a thickness of 80 μm was produced as an embossed plate from this prototype by electroplating.

(2) Preparation of 2nd composition for transparent layer formation The component of the following composition was mixed and the 2nd composition for transparent layer formation was prepared.
-Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA30, Nippon Kayaku Co., Ltd.); 50 parts by weight- Isocyanuric acid ethylene oxide-modified triacrylate (M315, manufactured by Toagosei Co., Ltd.); 50 parts by weight- Toluene (solvent); 100 parts by weight Photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl ketone) (trade name Irgacure 184, manufactured by Ciba Specialty Chemicals); 3 parts by weight

(3) Formation of second transparent layer The second transparent layer-forming composition was applied to the surface of the first transparent layer where the fine irregularities were formed using a wound coating rod. The film was kept in an oven heated to 60 ° C. for 30 seconds, the solvent was dried, and then the coating film was cured by irradiating ultraviolet rays so as to have an integrated light quantity of 98 mJ. 50) was provided on the first transparent layer to produce a translucent article according to the present invention.

<Example 2>
(1) Formation of fine irregularities in the first transparent layer Easy adhesion treatment of a transparent biaxially stretched PET film (refractive index: 1.66, Toyobo product name; Cosmo Shine A4100) having a thickness of 100 μm and one surface easily adhered. The primer layer-forming composition described below was applied to the uncoated surface by gravure coating to a film thickness of 500 nm, heated at 70 ° C. for 1 minute, and the solvent was dried. Then, it heated at 120 degreeC and embossed to the primer layer similarly to Example 1, and formed the fine unevenness | corrugation.
[Primer layer forming composition (refractive index: 1.63)]
The following (A) and (B) were mixed and used at a ratio of A / B = 6/4 at the time of use.
(A)
Amorphous polyester (trade name Byron 280, manufactured by Toyobo); 95 parts by weight. Toluene / methyl ethyl ketone = 1/1 weight ratio mixed solvent; 5 parts by weight (B)
Rutile-type titanium oxide particles (trade name MT-01, manufactured by Teica); 10 parts by weight Dispersant (trade name, Disperbic 163, manufactured by Big Chemie Japan); 2 parts by weight Pentaerythritol triacrylate (trade name, PET30, Japan) 4 parts by weight-titanate coupling agent (trade name TA-25, manufactured by Matsumoto Kosho); 1.28 parts by weight-photopolymerization initiator ((1-hydroxy-cyclohexyl-phenyl ketone) trade name Irgacure 184, manufactured by Ciba Specialty Chemicals); 0.2 parts by weight; methyl isobutyl ketone (solvent); 17.48 parts by weight

(2) Formation of second transparent layer The second transparent layer was formed in the same manner as in Example 1, and the translucent article of Example 2 was produced.

<Example 3>
The translucent article of Example 3 was manufactured in the same manner as Example 2 except that the composition of the second transparent layer was changed to the following to form a second transparent layer having a refractive index of 1.56. .
[Second transparent layer forming composition]
9,9-bis [4- (2acryloyloxyethoxy) phenyl] fluorene (trade name, NK ester A-BPEF, manufactured by Shin-Nakamura Chemical Co., Ltd.); 2.5 parts by weight Bis [(2-methacryloylthio) ethyl ] Sulphide (trade name S2EG, manufactured by Sumitomo Seika); 2.5 parts by weight dipentaerythritol hexaacrylate (trade name DPHA, manufactured by Nippon Kayaku); 3 parts by weight pentaerythritol triacrylate (trade name PET30, Nippon Kayaku) 2 parts by weight / photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl ketone, trade name Irgacure 184, manufactured by Ciba Specialty Chemicals); 0.3 parts by weight / photopolymerization initiator ((2, 4,6-Trimethylbenzoyl-diphenyl-phosphine oxide) Trade name DAROCURE TPO, Ciba Specialty Chemicals Inc.); 0.3 parts by weight Methyl ethyl ketone (solvent); 10 parts by weight

<Comparative Example 1>
A translucent article of Comparative Example 1 was produced in the same manner as in Example 1 except that fine irregularities were not formed on a transparent biaxially stretched PET film having a thickness of 100 μm, on which one surface was easily adhered.

<Comparative example 2>
A translucent article of Comparative Example 2 was produced in the same manner as in Example 2 except that fine irregularities were not formed on the primer layer.

<Comparative Example 3>
A translucent article of Comparative Example 3 was produced in the same manner as in Example 3 except that the fine irregularities were not formed on the primer layer.

<Comparative example 4>
A translucent article of Comparative Example 4 was produced in the same manner as in Example 2 except that fine irregularities were not formed on the primer layer and the second transparent resin layer was not formed.

[Performance evaluation method]
The following points were evaluated with respect to the translucent articles of Examples and Comparative Examples obtained above. The evaluation results are shown in Table 1.
(1) Presence / absence of interference fringes In the translucent article, in order to prevent the influence of back surface reflection caused by the side where the second transparent layer is not laminated among the surfaces of the first transparent layer, the second transparent The surface of the first transparent layer on the side where the layers are not laminated is rubbed with sandpaper, a black tape is pasted on it, and an interference fringe inspection lamp (FNA-18 manufactured by Funatech Co., Ltd.) and a three-wavelength fluorescent lamp The translucent article was visually observed from the surface of the 2nd transparent layer, and the following evaluation criteria evaluated.
(Evaluation criteria)
◯: No interference fringes were generated for both the interference fringe inspection lamp and the three-wavelength fluorescent lamp.
X: Interference fringes were generated for both the interference fringe inspection lamp and the three-wavelength fluorescent lamp.

(2) Total light transmittance Based on JIS-K7105, total light transmittance (%) was measured using haze meter HR100 (Murakami Color Research Laboratory make, brand name).

<Summary of results>
In the translucent article which has fine irregularities of a specific shape according to the present invention at the interface between adjacent two layers having different refractive indexes, the interference fringes generated when the fine irregularities are not present. However, it became clear that it became unobservable.
According to the evaluation result of the article manufactured this time, when the difference in refractive index between the adjacent two-layer interfaces was 0.03, no interference fringes were observed even without fine irregularities at the interfaces. When the difference in refractive index was 0.07 or more, interference fringes were recognized if there were no specific fine irregularities on the interface.
Moreover, by forming fine irregularities of a specific shape according to the present invention at the interface, the total light transmittance was improved by 1.5 to 1.7% compared to the case where the fine irregularities were not provided. This is presumably because the transmitted light loss due to the reflection that originally occurred at the interface was reduced due to the fine irregularities.

It is sectional drawing which illustrates one form of the translucent article which concerns on this invention. It is sectional drawing which illustrates one form of the translucent article which concerns on this invention. It is sectional drawing which illustrates one form of the translucent article which concerns on this invention. It is a figure for demonstrating notionally the distribution of the effective refractive index obtained by a fine unevenness | corrugation. It is a figure for demonstrating notionally the distribution of the effective refractive index obtained by a fine unevenness | corrugation. It is a figure for demonstrating notionally the distribution of the effective refractive index obtained by a fine unevenness | corrugation. It is sectional drawing for notionally comparing and explaining the shape of a fine unevenness | corrugation with a vertical cross-sectional shape. It is sectional drawing for notionally comparing and explaining the shape of a fine unevenness | corrugation with a vertical cross-sectional shape. It is sectional drawing for notionally comparing and explaining the shape of a fine unevenness | corrugation with a vertical cross-sectional shape. It is the perspective view and top view which illustrate some arrangement | positioning in the horizontal surface of a fine unevenness | corrugation. It is a top view which shows another example in the horizontal surface of a fine unevenness | corrugation. It is sectional drawing which illustrates one form of the translucent article which concerns on this invention. It is sectional drawing which illustrates one form of the conventional translucent article. It is sectional drawing which illustrates one form of the conventional translucent article.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A 1st transparent layer 1B 2nd transparent layer 2 Fine unevenness | corrugation 2A-2G Fine unevenness | corrugation 2 Shape of _Mb trough side 2 Shape of _Mt mountain side 2b Most concave part 2t (of fine unevenness) Most convex part 10 Through light article 11 fine uneven layer 12 transparent layer substrate _T 1 through T ₄ transparent layer I of the adjacent two layers interface L _iN incident light L _OUT transmitted light P small projections surfaces n the refractive index n _a first formed Refractive index n _b of transparent layer n _b Refractive index n _ef of second transparent layer (Z) Effective refractive index H (fine unevenness) height H / 2 (half height of fine unevenness (1/2)
H _MAX Height of the most convex portion (of the fine irregularities) Lb (Valley side) Contour line Lt (Crest side) Contour lines Mb Fine irregularities of the valley side Mc Fine irregularities of the ridge Mt Fine irregularities of the mountain side PMAX Period
Wb Width of the valley portion Wb1 Width of the valley portion on one side of the mountain Wb2 Width of the valley portion on the other side of the mountain Wt Width of the mountain portion

Claims (1)

A translucent article comprising a laminate of transparent layers including at least one pair of adjacent two layers having different refractive indices, and having fine irregularities at least one set of interfaces of the adjacent two layers,
When the minimum wavelength in the vacuum of the visible light wavelength band is λMIN and the period at the most convex portion of the fine unevenness is PMAX,
PMAX ≦ λMIN
Have the relationship
In addition, when it is assumed that the fine irregularities are cut along a plane orthogonal to the irregular direction, the cross-sectional area occupancy of the transparent layer on the side where the most convex portions are formed in the cross section is the highest from the most convex portions of the fine irregularities. A translucent article characterized by increasing continuously and gradually as it goes to the recess and becomes 100% in the most recess.

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